Balanced sheave



T. A. COLEMAN. BALANCED S HE-AVE. APPLICATION FILED SEPT. PI, 1919.

Patented Aug. 31, 1920.

TORNE).

UNITED STATES Parent caries.

THoMAs A. coLEMAN, or BLYTHEVILLE, AaKANsAs.

BALANCED I full, clear, and exact description, such as will enable others skilled in the art towhich it appertains to make and use the same, refer ence being had to the accompanying drawings, forming part of this specification.

My invention relates to a sheave or grooved pulley which serves as a support or bearing for a rope or cable, the principal object of my invention being to provide a sheave that is particularly applicable for use on the booms of log slridders and which latter, it will be understood, are utilized for dragging loss from all directions to a central point where they are loaded onto trans-' porting means such as cars. I

It will be understood that in operation,

the log hauling cable is extended away from the boom of the skidder so as to be connected to logs lying within a radius of several hundred feet from said skidder, and in order that said cable will work to the best advant-ge, it is essential that the sheave over which said cable travels should be pivotally mounts ed so as to shift its position or swing toward the direction of pull of the cable, and to this'end I propose to mount the sheave in a housing that is provided with alined trunnions and the latter being journaled in suitable bearings on the boom, thus enabling the sheave to swing freely sidewisein both directions.

A further ob ect of my invention is to provide the upper portion of the sheave block or frame with a weight designed to counterbalance the weight of the sheave and the lower portion of the block, thus providing a balanced structure which does not imweight upon the cable while the same is extended laterally from the boom and is under pulling strains.

Vfith the foregoing andother' objects in view, my invention consists in certain novel features of construction and arrangement of parts, hereinafter more fully described and claimed, and illustrated in the accompanyino drawings, inwhichr igure 1 is an elevational view partly in section of the outer end of the boom of a I Specification of Letters Patent. V Paten fl Aug, 31-, lpplioation filed September 11,1919. Serial no. 323,133.

log skidder and showing a balanced'sheave, of my improved lCOHStl'LlClJlOIl in position thereupon.

Fig. 2 is a plan view of the outer end off 7 a log skiddin boom and showing my im q.

proved sheave in position thereupon.

Fig. 8 is a vertic'ial section taken one center line through a'sheave of my improved construction. 7 y F 1g. 4 18 an end view ofjthesheave.

Referring by numerals to the'accompany ing drawings, 10,- 10 designate the side members of a'log skidding boom, and 11, 11 a pair of transversely disposed rails or members which are framed tosaid side members.

Formed on or fixed tothese transverse members 11 are bear1ngs12 which are adapted to receivethetrunnionson the sheave block or frame and which latter comprises a pair of substantiallyparallel[plates or side members 13, the upper portions/of which are connected by a block 1 1. These side members 13 and block 14 may be formed integral with each other by'casting or they may be formed in separate pieces and connected to each other by beingwelded together or by means of bolts or rivets.

Formed integral with the endsof'the block 1 1 are tubular trunnions 15 which are ournaled in the bearings 12, and thus the sheave block or frame is mounted so as torock or 7 swing laterally while in service.

The side members 13 are provided with centrally arranged bearings 16 which receive a pin or short shaft 17 and carried bythe latter is a sheave or grooved pulley 18 of ordinary construction. The diameter of this sheave is such thatits peripheral portion travels in a path that is in direct alinement with the openings through the tubular trunnions 15. This sheave "receives, the usual cable A, which passes through the inner one of the trunnions 15 andthroughan aperture formed in the inner one of the transverse members 11. This cableis guidedby small drums B, the latter being mounted in suitable hearings on the boom adjacent to the in-,'' ner one ofthe cross members 11. v I A sheave so constructed and mounted has its grooved periphery in direct alinenient with that portion of the cable between the outer end of thebooin and the winding drum positioned on the body of the skidder and as the sheave'carrying block is free to rock in the bearings 12, said sheave will readily swing from one side to the other to accommodate the pull of the cable under working conditions. By virtue of this arrangement, the wear upon the sheave from the cable during service is minimized.

It will be understood that the weight of block 14 serves to counterbalance the weight of the sheave and the lower portions of the side members 13 of said block, and thus the cable is relieved of all weight of the sheave while in operation and under such conditions, the cable can be readily drawn outw ardly away from the boom to be attached to a log. r

In the event that the trunnion which is positioned in the inner one of the bearings 12 becomes worn from contact with the cable, the entire sheave can be reversed or turned end for end, thereby bringing the unworn trunnion into position adjacent to the inner one of the transverse members 11.

A balanced sheave of my improved construction is comparatively simple, can be easily and cheaply manufactured, and is very effective in performing its intended functions. 7 s

It will be readily understood that minor changes in the size, form and construction of the various parts of my improved balanced sheave can be made and substituted for those hereln shown and described, wlthout departing from the spirit of my invention, the scope of which is set forth in the ap pended claims. 7

I claim:

l.- A balanced sheave comprising a pair of 7 trunnions on the ends of said weight, the

openings in which tubular trunnions are in direct alinement with each other, and a sheave 'ournaled between said plates. 7

ILA balanced sheave comprising'a'counand depending from said weight, a

' "ral tubular trunnions projecting outwardly from the ends of the counterbalanced weight adjacent to the upper outer corners c" said plates, the openings in which tubular trunnions are in direct'alinement with each other and with the grooved periphery of said 7 sheave.

In testimony whereof I hereunto affix my signature this 8th day of EleptembelglSlQ.

- THOMAS a. COLEMAN;

erbalancing weight, a pair of plates spaced heave journaled between'said plates, in 

